I bought an Apple Airport Express last year and have been very happy with it: it allows me to play music on iTunes on my laptop but have the sound come from my stereo speakers... it's all done wirelessly. Cool!
One extra feature of the device, which I hadn't used until now, was its printing support: you can plug a USB printer into it. I've just tried it and it works just great: I can now print wirelessly to the printer without having to attach the printer to a computer or replace it with one that understands networking. Fantastic stuff.